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HOW TO STUDY 

ILLUSTRATED THROUGH PHYSICS 

By 
FERNANDO SANFORD 



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Ibow to Stufcs Series 

HOW TO STUDY 

Illustrated through Physics 



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BY 

FERNANDO SANFORD 

FORMERLY PROFESSOR OF PHYSICS, 
LELAND STANFORD UNIVERSITY 



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THE MACMILLAN COMPANY 

1922 

All rights reserved 



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54 



Copyright, 1922, 
By THE MACMILLAN COMPANY. 



Published February, 1922. 



©CI.A653985 



PRINTED IN THE UNITED STATES OF AMERICA 



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1 1322 



INTRODUCTION 

Nearly everywhere the principal emphasis in 
instruction is on knowledge. Tests or examina- 
tions on knowledge are the basis of ratings and 
promotions, and therefore the goal both of pri- 
vate study and of class work. While method is 
a frequent subject of discussion, it is the method 
rather of the teacher than of the learner, and 
even it is judged by the extent to which it leads 
to acquisition of knowledge. The fact that young 
people have a method of their own, that its 
quality is of vital importance, and that it needs 
great improvement is generally overlooked; for 
it is unrelated to tests. 

A very different conception of teaching is 
represented in this monograph. Physical Science 
is shown to owe its progress to improvement in 
the method of studying it; and as a result of such 
improvement a single day now brings a greater 
advance in knowledge of the physical world than 
did the first thousand years of the Christian era. 

Since method has been the secret of the 
marvelous progress, the principal object of in- 
struction in Physics should not be merely the 

iii 



IV INTRODUCTION 

comprehension of a lot of facts or even laws, but 
rather the control of the method of investigation 
that has proved so fruitful in the discovery of 
those facts and laws. Furthermore,, Physics 
should be primarily a study of scientific method, 
because skill in that method has a much broader 
application than knowledge of subject matter in 
that field. 

The implications for general Education in this 
point of view are far-reaching. If the idea is 
sound, the principal object of instruction in some 
or possibly all other subjects might well be 
greatly modified, and the method of the learner 
might be brought into prominence. And since 
Physics offers the most nearly perfect example 
of the scientific method, it might be taken as 
the standard for the other subjects; they differ 
from it rather in degree than in kind. 

How sound are such implications? Certainly 
modern Education is moving toward this point 
of view. For illustration, during the last few 
years the pupil's method of reading has been 
extensively studied by educational specialists and 
in many schools improvement in that method has 
already become a prominent purpose in the teach- 
ing of Reading. The method of the learner is 
slowly receiving recognition. 

There are several reasons. The child's enjoy- 



INTRODUCTION V 

ment of school is very dependent upon his skill 
in study ; so also is his real digestion of any sub- 
ject studied. But even more important is the 
thought that method in any given field, just as 
in Physics, has a far wider application to life's 
problems than subject matter; that control of 
method is largely the same as mental discipline, or 
power. In consequence, students should be 
examined and rated at least as much on their 
method of procedure as upon their knowledge of 
subject matter. 

Thus there are large possibilities suggested in 
these pages. But one should understand that 
movement toward realization of these possibilities 
must be very slow. The demand is that one shall 
learn to think, independently and skilfully, in 
each field studied. That is not only a radical, it 
is a revolutionary demand; for thinking is a very 
different thing from acquisition of knowledge. 
Many curricula and textbooks of the present 
time fail even to meet the conditions that allow 
good thinking; they must be made over before 
a good start can be made toward thinking. 
Also, since the pupil or student is the one that 
is to be taught to think — to propose the questions 
as well as to find their answers — teachers must 
learn to keep still in the classroom much more 
than at present, while, at the same time, stimu- 



VI INTRODUCTION 

lating activity. In short, since emphasis on 
method of study requires subordination of both 
subject matter and teacher to the learner, a 
radical change in the teacher's point of view, in 
the very purposes of instruction, is involved. At 
present not one teacher in one hundred would 
dare attempt to give demonstration lessons show- 
ing how to do "good thinking" in the lessons as- 
signed; and a great majority of teachers could 
not now show the difference between memorizing 
a text and good thinking. 

It will be a long time, therefore, before the 
various studies in school and college will follow 
the lead of Physics in the emphasis on method 
suggested in this monograph. Yet that is not 
too discouraging. We see the direction we have 
to travel; and if the road is long, it is high time 
that the journey be commenced. 

Frank M. McMurry, 
Teachers College, 

December 15, 1921. 



HOW TO STUDY 

ILLUSTRATED THROUGH PHYSICS 



HOW TO STUDY: 

ILLUSTRATED THROUGH PHYSICS 

The influence of purpose in method of study. 

— It is plain that any study may be pursued from 
a variety of motives, and that each one of these 
motives may influence to a greater or less degree 
the method of study to be adopted. Thus one may 
study history in order to pass a prescribed ex- 
amination, he may study it in order to appear in- 
telligent and well informed in society, he may 
study it in order to apply its lessons in politics or 
social matters, he may study it in order to gain a 
livelihood by teaching it to others, or he may study 
it simply because he wants to know. Any of 
these motives may influence his selection of sub- 
ject matter and his method of pursuing the study. 
What has been said of the variety of motives 
which may lead to the study of history is just as 
true of the reasons which may be given for study- 
ing physics,, and in this case, since there are more 
methods of study open to the student of physics 
than to the student of history, the method of 



2 how to study: 

study will be determined by the motive much more 
in the case of the former than of the latter. 

Thus, consider the single case of preparing 
for an examination in physics. The questions 
asked may refer merely to the statement of gen- 
eral laws (and these may frequently be stated 
either in words or in mathematical formulae) 
or they may require a knowledge of how to apply 
these laws to a specific case. They may be quali- 
tative, that is, they may require a descriptive 
answer, or they may be quantitative and require a 
numerical answer. They may, and often do, re- 
quire an experimental demonstration. If the can- 
didate for examination knows beforehand which 
kinds of questions are likely to be asked,, he will 
do wisely to so modify his methods of study as to 
get the best possible preparation for the coming 
examination with the least amount of effort. He 
may prepare for one examination by the study 
of a single textbook, while in another case it may 
be necessary for him to get his preparation in a* 
library or in a laboratory. 

If the student of physics has some other aim 
than the mere passing of a set examination, his 
possible methods of study may be still more 
numerous. Accordingly, before a student is qual- 
ified to decide for himself upon a method of 



ILLUSTRATED THROUGH PHYSICS 3 

studying physics, it is highly important for him to 
be informed in regard to the possible methods of 
studying this science which are open to him, and 
to have a tolerably clear comprehension of the 
aims which he hopes to accomplish by the study. 

There are, in general, two partially distinct 
methods of science study which may, to some ex- 
tent, be contrasted with each other. One of these 
is the method which is usually most encouraged 
in our schools and colleges, and which leads to 
what we know as scholarship. It consists largely 
in learning what has been known and what has 
been thought by the men whom the world has 
recognized as leaders in scientific thinking, and in 
trying to comprehend their thoughts and to think 
them over again as if they were our own. Thus, 
for more than a thousand years approved scholar- 
ship in science throughout Europe consisted in 
accepting and in comprehending more or less per- 
fectly the teaching of Aristotle. At the present 
time, it consists largely in accepting and in trying 
to comprehend the teachings of a few recognized 
leaders in each department of science. 

The other method of science study results from 
the attempt on the part of the student to acquire 
not only the knowledge which has been left to us 
by our masters of a previous age, but to cultivate 



4 how to study: 

the mental habits which enabled these men to 
become leaders of scientific thinking in their gen- 
erations. 

The dependence of progress on the purpose 
adopted. — As a result of the greater prevalence 
of the training for scholarship than for scientific 
leadership, a few men in each generation are still 
compelled to do the real thinking for the whole 
world, while the rest of us are content to be 
merely their disciples. In this respect there has 
been but little improvement in recent times. Thus 
the following paragraph, which was written by 
Joseph Priestley in 1767, would be just as true if 
it were written to-day : 

Priestley says: 

I think that the interests of Science have 
suffered by the excessive admiration and 
wonder, with which several first rate philoso- 
phers are considered; and that an opinion of 
the greater equality of mankind, in point of 
genius,, and powers of understanding, would 
be of real service in the present age. It 
would bring more labourers into the common 
field; and something more, at least, would 
certainly be done in consequence of it. For 
though I by no means think that philosoph- 
ical studies are at a stand, I think the prog- 
ress might be quickened if studious and 
modest persons, instead of confining them- 
selves to the discoveries of others, could be 



ILLUSTRATED THROUGH PHYSICS 5 

brought to the idea that it was possible to 
make discoveries themselves. 

If it is true, as Priestley believed, that there is 
a greater mental equality of mankind than the 
results of science study in the past seem to indi- 
cate,, so that it is possible for "studious and 
modest persons'' to make original discoveries for 
themselves, a much nobler motive for the student 
of science is suggested than the mere desire 
for scholarship. Let us, before discussing this 
possibility, inquire more fully into the general 
nature of science study, and particularly into the 
special character of the science of physics. 

Reason for the many divisions of the field of 
science. — All science study results from the 
attempts of human beings to comprehend the uni- 
verse of which they are themselves a part. 

The universe is so great and so complex that 
all attempts at understanding it as a whole have 
failed; but by concentrating a great amount of 
thought and labor upon some small part of it at a 
time many things of great value have been 
learned. 

Since by this method of acquiring knowledge 
each investigator must work in a very limited 
field, the study of the universe has been under- 
taken along a great number of special lines which 
have come to be regarded as distinct sciences. 



b how to study: 

It should be remembered, however, that these 
divisions have been made by man merely for 
convenience in applying the principle of division 
of labor upon which most of his other work is 
based. To a mind capable of a complete compre- 
hension of the universe there would be but one 
science. 

Advantages for study that the physical sci- 
ences enjoy. — The division and classification 
of scientific knowledge into separate sciences has 
generally been based upon certain obvious dis- 
tinctions between the things about us. One of 
these distinctions is between living and nonliving 
things. The differences between these two classes 
of things are very great. Since we, ourselves, are 
living beings, our interest in living things is nat- 
urally very much greater than in nonliving, or 
inanimate, things. Unfortunately, the complex 
changes which are constantly going on in living 
bodies are much more difficult to comprehend 
than are the changes which are taking place in 
inanimate bodies. Besides, many of the methods 
which are employed in the study of inanimate 
bodies cannot be applied to the study of living 
bodies without destroying life. For these rea- 
sons, much greater progress has been made in 
understanding the relations between the changes 
in nonliving than in living bodies. 



ILLUSTRATED THROUGH PHYSICS J 

Since most of the changes which are going on 
in nonliving bodies are also taking place in living 
bodies, we may learn much about the latter by a 
study of the former. In fact, almost the only 
phenomena of living bodies for which satisfac- 
tory explanations have been found are those 
which are also common to nonliving bodies. 

The special purpose of physics. — The science 
of physics has to do wholly with nonliving bodies 
and their relations to one another. The changes 
which are continually taking place in and between 
these bodies are very numerous, and some of them 
are very complex. It is the purpose of the science 
of physics to determine under what conditions 
and, if possible, why certain changes always 
occur. When these conditions are known, they 
enable us to predict or to bring about desirable 
changes. 

Our slowness in accomplishing this purpose. 
— It is only within the past three hundred years 
that mankind has begun to learn how to predict 
with certainty the physical changes which will 
occur under specified conditions. Before that 
time such knowledge was usually acquired acci- 
dentally, if at all. Once every few hundred years 
some man was born who seemed to have a special 
insight into the workings of nature, and such a 
man always made important discoveries; but he 



8 how to study: 

did not succeed in teaching other men how to 
make the same kinds of discoveries, and he was 
generally looked upon as a very superior or as a 
very dangerous person. Other men came to ac- 
cept his merest opinions as authority in matters 
of science, or to look upon him as in league with 
the Devil. Often both opinions concerning him 
were held at the same time by different people. 

It has thus come about that a very few men 
have done nearly all the important scientific think- 
ing of the world. Most of what has passed for 
scientific study has resulted from the attempts of 
other men to find out what these few leaders have 
thought and, if possible, to think the same 
thoughts over after them. 

The attempt to do even as much as this did not 
come early in our civilization. It has always been 
the tendency of human beings in the state of 
intellectual infancy to attribute the movements of 
material bodies to acts of will on the part of 
some being superior to themselves. It is in this 
way that most of the religions of the world have 
arisen. Accordingly, although the Greeks were 
apparently the earliest people to look for physical 
causes for natural phenomena, it has been said 
that the Greeks of Homer's time would not have 
thought of asking the cause of rain or thunder 



ILLUSTRATED THROUGH PHYSICS 9 

or earthquakes, but instead, who rains, or who 
thunders, or who shakes the earth. 

The discovery that has made physical science 
possible. — The fact that many of the changes 
which take place in nonliving bodies in our uni- 
verse depend upon some kind of relation between 
the bodies themselves, and not upon the wills of 
gods or demons or other spiritual beings, is one 
of the greatest discoveries ever made by the 
human mind. Until this discovery was made all 
physical science was impossible; for if a given 
phenomenon might be caused by one god or one 
spiritual power at one time and by some other 
god or spiritual power at another time, it would 
be impossible to tell when this phenomenon was 
going to occur, or what means to take to bring it 
about or to prevent its occurrence. Accordingly, 
it was not until it was recognized that there is a 
part of the universe in which spiritual powers 
seem to play no direct part, and in which every 
action or change taking place is the inevitable 
consequence of some previous action or change, 
that it was possible to have a physical science. 

That part of the universe in which mental or 
spiritual powers never intervene is known as the 
physical universe. The main purpose of the study 
of physical science is to acquire a comprehension 



IO HOW to study: 

of the relations which lead to inevitable changes 
in the physical universe. It is upon our knowl- 
edge of these relations that our mastery of the 
physical universe depends. 

Meaning of Natural Law. — When these in- 
variable relations between physical phenomena 
have been discovered and described they are 
known as natural laws. Thus it has always been 
observed that a heavy body when unsupported by 
another body falls to the earth, or continues to 
fall until it is supported by another body. We 
can accordingly say that it is "a law of nature" 
that an unsupported body falls toward the earth. 
No one knows why it falls. We have learned how 
far it will fall in each second that it is free and 
how great its speed will be at the end of each 
second of falling. These facts, when combined 
into an intelligible statement, constitute what is 
known as The law of falling bodies. 

It will be seen that the word "law" is not here 
used with its customary meaning. In the most 
common usage, a law means a decree or enact- 
ment by a ruler or a governing body. Such a 
law may be obeyed or disobeyed. Generally a 
penalty is prescribed for disobedience, but this 
penalty is not always enforced. 

Another common meaning of the word law is 
that of a usage or custom. Thus a law of gram- 



ILLUSTRATED THROUGH PHYSICS II 

mar or spelling is merely the statement of what 
has come to be a customary usage. These laws 
have not, in general, been decreed, and when cer- 
tain decrees have been announced by some or- 
ganized body, as, for example, The Simplified 
Spelling Board, the body issuing the decree has 
no authority to enforce it. 

A natural law differs from a decree or usage 
in that it is a statement of a universal, and hence 
inevitable, order of events. A decree may be 
disobeyed, regardless of consequences. The 
usages upon which the laws of grammar and 
spelling rest are very far from being universal, 
and are generally incapable of being so stated 
that there are not many exceptions to them. But 
a law of nature is not subject to a single excep- 
tion. If a single heavy body could be lifted 
without the expenditure of energy or if it could 
remain unsupported above the earth, then would 
our whole present science of physics be over- 
thrown. 

Importance of our knowledge of natural 
laws. — Huxley has given one of the best state- 
ments of our reasons for wishing to acquire a 
knowledge of natural laws. He says : 

It is a very plain and elementary truth 
that the life, the fortune and the happiness 
of every one of us and, more or less, of those 



12 HOW TO study: 

who are connected with us, do depend upon 
our knowing something of the rules of a 
game infinitely more difficult and compli- 
cated than chess. It is a game which has 
been played for untold ages, every man and 
woman of us being one of the two players 
in a game of his or her own. The chess 
board is the world, the pieces are the phe- 
nomena of the universe, the rules of the 
game are what we call the laws of nature. 

Education is learning the rules of this 
mighty game. In other words, education is 
the instruction of the intellect in the laws of 
nature, under which name I include not 
merely things and their forces, but men and 
their ways ; and the fashioning of the affec- 
tions and the will into an earnest and loving 
desire to move in harmony with those laws. 

Huxley seems to suggest that it is possible to 
be out of harmony with nature's laws, and in 
another place he speaks of the penalty of dis- 
obedience to natural laws ; but in the strict sense 
a disobedience of nature's laws is an impossibility. 
A man who leaps from a high cliff is not punished 
for disobeying any law of nature; on the con- 
trary, he obeys the law of falling bodies and 
takes the consequences. The so-called penalty 
which he pays is only an additional proof of the 
invariableness of natural law. The same thing 



ILLUSTRATED THROUGH PHYSICS 13 

may be said of a man who contracts a contagious 
disease or indulges in the excessive use of alcohol 
or deprives himself of necessary food; he does 
not disobey the laws of nature — he merely exem- 
plifies them in his own person. 

Our knowledge of the laws of nature accord- 
ingly will not shield us from disobedience to them,, 
because the very existence of a law precludes any 
possibility of disobedience to it; but while we can- 
not disobey a natural law if we would, we may, 
by understanding these laws,, often avoid the 
unpleasant results of certain relations between 
ourselves and external things. If we thoroughly 
understand the rules of the game, we may predict 
the consequences of our moves before we make 
them. 

Two methods of learning natural laws. — 
How, then, shall we learn the rules of this mighty 
game ? Attention has already been called to two 
general methods which we may designate for our 
purpose as the method of the scholar and the 
method of the scientist. The former, we have 
seen, consists in learning from books and lectures 
what other men have thought about the laws of 
nature and in trying to think their thoughts over 
after them. This method leaves all the real 
thinking to a few men, while the rest become 
merely their disciples. 



14 how to study: 

As has already been said, much the greater 
part of the physics teaching of the schools is 
based upon this method. We are given the 
opinions of Galileo and Newton and Faraday as 
to what constitute the rules of the game. We 
learn the stock arguments in favor of these 
opinions and we perform experiments and solve 
problems in order that we may have a clear un- 
derstanding of the opinions which we accept; but 
we are given no opportunity of forming an inde- 
pendent opinion on the basis of our own seeing 
and thinking; and, what is still more to be de- 
plored, we are given no training in the method of 
science study which made Galileo and Newton 
and Faraday our scientific authorities, and which, 
though used by but few men, has completely revo- 
lutionized our civilization in only three hundred 
years. 

And yet the method of the scientist is not neces- 
sarily more difficult than the method of the 
scholar, for it is sometimes more difficult to un- 
derstand the laborious and involved thinking of 
some of the leaders whom custom has selected as 
our guides to scholarship than it is to get, by our 
own efforts, a much clearer understanding of 
the relations which they are trying to explain. 
Let us, then, consider the method of the scien- 
tist. 



ILLUSTRATED THROUGH PHYSICS 1 5 

Modern physical science compared with the 
old natural philosophy. — It is more than two 
thousand years since it was recognized by Grecian 
philosophers that the changes which take place in 
the physical universe are not merely the arbitrary 
acts of some god or demon, but are the inevitable 
consequences of physical conditions. Since this 
discovery was made, many of the keenest minds 
of the world have been devoted to the discovery 
of natural laws and a comprehension of their re- 
lations to each other. Down to the year 1600 
these efforts were almost wholly without suc- 
cess. Previous to this time the human race 
had apparently reached its highest possible 
achievements in many lines of intellectual en- 
deavor. In religion, in philosophy, in logic, in art, 
in music, in architecture,, in literature, people still 
turn to the "old masters" for their models and 
their inspiration. In science there were no old 
masters. 

Yet in the three hundred years that have 
elapsed since 1600 the whole character of our 
civilization has been revolutionized and most of 
our habits of thought have been changed by the 
marvelous development of physical science. It is 
safe to say that during any day of the year just 
passed greater scientific advancement was made 
than in the first thousand years of the Christian 



1 6 how to study: 

Era. It would seem that a method of study which 
has led to such tremendous achievement in even a 
single line of thought would be immediately 
adopted by at least all the workers in that par- 
ticular field, even though it could not be applied 
elsewhere; but the painful admission must be 
made that the scientific method of study, like 
many well-known virtues, is highly commended 
and seldom practiced. 

Yet it must be true that if there is a peculiar 
method of studying physical science, the use of 
which has so greatly modified our civilization, the 
acquisition of this method of study and of think- 
ing should be the most important aim of our 
education. It is when we undertake to explain 
this "scientific method" that the really hard part 
of this discussion begins. It is easy to write 
about textbook methods and lecture methods and 
laboratory methods, but it is very difficult to 
specify clearly what we mean by these methods. 
This is especially true of the so-called laboratory 
methods. It is difficult to find any considerable 
number of textbooks the authors of which would 
use the physical laboratory from the same mo- 
tives. To a less degree,, the same may be said of 
the different uses made of textbooks and lectures. 

However, it is possible to show important 



ILLUSTRATED THROUGH PHYSICS 1 7 

differences between the Greek methods of study- 
ing natural philosophy which prevailed down to 
the year 1600, and the methods of studying 
physics to-day. The Greeks gave a great deal of 
thought to Natural Philosophy, but, as we have 
seen, they made very little progress in the in- 
terpretation of nature. This appears to have been 
true partly because they made very inaccurate 
observations, and partly because they tried to 
settle questions in physical science in the same 
way that we now try to settle questions in what 
we call the political and social sciences, namely, by 
arguing about them. It should be remembered 
that the reason why a question may be argued is 
because the true answer to it has not been found. 
So it happened that while the Greeks were the 
best debaters and the keenest logical reasoners 
that the world has produced, they could make no 
progress in physical science. 

Another reason for failure in the science study 
of the ancients lies in the fact that in those days 
men tried to discover what has been called the 
essence of things ; that is, they tried to find some 
general principle from which all the phenomena 
of the physical universe could be logically de- 
duced, instead of trying to find out merely the 
relations between these phenomena. 



1 8 how to study: 

Perhaps a fair characterization of the common 
method of the natural philosophy of those days 
may be put in this way: the ancients tried to 
imagine the nature of the first cause from which 
the universe sprang or of the deity by whom it 
was created; then from their conception of this 
first cause or deity they drew their conclusions as 
to what kind of universe must have resulted or 
must have been created. 

A similar point of view, which was held by 
some ancient philosophers as well as by a con- 
siderable number of more modern ones, is that 
the human mind is but the duplication on a 
smaller scale of the mind of the Creator; and 
that consequently we may, when undisturbed by 
external conditions, think over again the thoughts 
of the Creator, and thus arrive at a comprehen- 
sion of the physical universe. Unfortunately, 
this method has never given an interpretation of 
the universe which even remotely coincided with 
observed relations. 

Method of Roger Bacon and Leonardo da 
Vinci. — But even in the days when these fruit- 
less methods of studying the universe were al- 
most invariably adopted, an occasional man ap- 
peared who seemed to have some peculiar insight 
into natural phenomena. It may be worth while 
to inquire how these men studied physics. 



ILLUSTRATED THROUGH PHYSICS 19 

One such man was Roger Bacon, a learned 
monk, who lived in England seven hundred years 
ago. Bacon wrote : 

We have three means of arriving at 
knowledge: authority, reason, experiment. 
Authority has no value if its basis is not un- 
derstood ; it teaches nothing, but merely calls 
out our assent. By reason we may distin- 
guish a sophism from a demonstration, while 
we may test our conclusions by experiment. 

It will be seen that Bacon suggests experiment, 
instead of argument, as a means of testing con- 
clusions. However, his suggestion seems to have 
had no influence upon the scientific method of his 
time. 

Three hundred years later there was living in 
Italy one of the famous men of history. Leonardo 
da Vinci was celebrated as a painter, sculptor, 
architect, engineer, anatomist, botanist, astrono- 
mer, poet, and musician, and he was also the 
greatest physicist of his time. It would seem that 
Da Vinci must have had superior methods of 
study in order to accomplish so much, no matter 
how great his genius. Fortunately, he has told 
us something of his method of studying physics. 
He says: 

In undertaking scientific investigations, I 
first plan a few experiments, because it is my 



20 HOW to study: 

design to base the problem on experience and 
then to determine why the bodies in question 
are constrained to act in a given manner. 
This is the method that one must adopt in 
all researches. It is true that nature begins 
with reason and ends in experience, but, 
nevertheless, we must choose the opposite 
way; we must, as I have already said, begin 
with experience and through its means strive 
for a recognition of the truth. 1 

Thus Da Vinci suggests that before attempting 
to find an explanation of a phenomenon by rea- 
soning about it, it is necessary to observe very 
carefully the relations to be explained. But his 
suggestions were not adopted by the other scien- 
tific men of his day, and it was not until a hundred 
years later that another physicist appeared in 
Italy. 

The change introduced by Gilbert and 
Galileo. — The year 1600 may be regarded as a 
turning point in the methods of scientific study. 
In that year Dr. William Gilbert published one of 
the great physical monographs of the world, in 
which he not only laid the foundation for the 
sciences of magnetism and electricity, but pro- 
posed and exemplified a new method of physical 
study. He says in his preface : 

1 Translated from Gerland's Geschichte der Physik. 



ILLUSTRATED THROUGH PHYSICS 21 

To you alone, true philosophers, ingenu- 
ous minds, who not only in books but in 
things themselves look for knowledge, have I 
dedicated these foundations of magnetic sci- 
ence — a new style of philosophizing. But if 
any see fit not to agree with the opinions 
here expressed and not to accept certain of 
my paradoxes; still let them note the great 
multitude of experiments and discoveries — 
these it is chiefly that cause all philosophy to 
flourish ; and we have dug them up and dem- 
onstrated them with much pains and sleep- 
less nights and great money expense. 

To the English speaking world, Gilbert may be 
regarded as the father of physical science. In 
his writings he constantly refers to the impor- 
tance of experiments. 

At the present time no physicist will give any 
consideration to physical interpretations which 
are not based upon experimental evidence, but this 
was not true of the philosophers of Gilbert's day, 
nor is it true of the average man of the present 
day. 

The greatest scientific man of ancient times 
was the Greek philosopher, Aristotle. His writ- 
ings were the chief textbooks of European 
scholars for more than a thousand years. His 
studies covered all the lines of thought of the 
ancient world, and determined what men should 



22 HOW TO STUDY: 

think during the middle ages. Throughout all 
this time approved scholarship consisted in trying 
to comprehend and adopt the opinions of 
Aristotle. 

Aristotle taught, among other things, that 
bodies of different weight fall with different 
velocities, and that the speed of fall is propor- 
tional to the weight. Thus, a ten-pound ball 
should fall ten times as fast as a one-pound ball. 
Everybody accepted this opinion, and no one 
tested it experimentally for two thousand years. 
Then, when Galileo dropped two cannon balls of 
unequal weight from the leaning tower of Pisa 
and invited the multitude to see that they both 
reached the pavement at the same time, the "scien- 
tists'' of that day believed that what they had 
apparently seen was a mortal error, and still ac- 
cepted the teaching of Aristotle in preference to 
the evidence of their own senses. 

The four necessary steps in the scientific 
method. — What has been said should be 
enough to make it plain that any study of physics 
should be based upon experiment, but it is plain 
that experiments may be used in various ways 
and for various purposes. For example, some 
teachers introduce them for the purpose of 
manual training, some use them as a means of 
illustrating or verifying the statements of text- 



ILLUSTRATED THROUGH PHYSICS 23 

book or lecture; and many, apparently, use them 
as a sort of busy work, to keep their students 
occupied. None of these methods is what is 
known as the method of science. Da Vinci tells 
us that he used experiments before beginning the 
study of a problem so that he might understand 
clearly the phenomena which he was undertaking 
to interpret. Roger Bacon says "we may test 
our conclusions by experiment. ,, Here are two 
distinct uses that may be made of experiment; 
namely, to enable us to understand clearly how 
the actions which we wish to explain actually 
take place, and to test our final conclusions as to 
the cause of the actions. 

Between these two appeals to experiment there 
are apparently two distinct mental processes 
necessary. In the first place, after getting a clear 
understanding from our first experiments of the 
character of the actions which we wish to explain, 
we make a guess at the probable explanation ; that 
is, we guess that a certain relation exists between 
the phenomenon which we are studying and some 
other phenomenon with which we are already ac- 
quainted. This guess is called an hypothesis or a 
generalization. The mental process concerned in 
its production is commonly known as induction. 

Then we say, "If our guess is correct, certain 
other phenomena which we have not yet observed 



24 HOW to study: 

must be produced by conditions which we can 
specif y." That is, we may predict new phe- 
nomena which have never been observed. This 
is logical thinking, or the mental process com- 
monly known as deduction. If our predictions 
have to do with the magnitude or the intensity of 
the expected result or with geometrical relations 
we may use mathematics in making our deduction. 
This is the only step in the scientific method in 
which mathematics comes into play. 

The fourth step in our scientific method is the 
testing of our predictions by experiment. Until 
this step is taken our scientific process is incom- 
plete ; after it is taken we can go no further except 
by making other predictions and testing them by 
experiment. If all our predictions stand the test 
of experiment we may conclude that our hypothe- 
sis is actually a natural law. Later, some more 
advanced thinker may find a logical deduction 
from it which does not stand the test, and then 
doubt is cast upon the validity of the law, and its 
statement must be changed to fit the new con- 
dition. 

An illustration of the difference between the 
scientific method and the method of argument. 
— To make our description of the scientific proc- 
ess as plain as possible, let us imagine a concrete 
example. Let us suppose that a traveler who has 



ILLUSTRATED THROUGH PHYSICS 2$ 

been accustomed to modern conditions in civilized 
communities is walking in an uninhabited wilder- 
ness at night when suddenly he sees in front of 
him two long shadows of himself stretching for- 
ward nearly parallel to each other. Let us sup- 
pose his first thought to be that an automobile is 
approaching him from the rear. This, then, is 
his hypothesis. 

If he uses the methods of the old Natural Phil- 
osophy, he will begin at once to argue with himself 
as to the probability or the improbability of an 
automobile's being in the wilderness. He will dis- 
cuss the possibility of its traveling over the route 
which he has followed. He may think of the 
swamps and rivers which he has crossed and of 
the mountains which he has climbed. He may 
recall all that he has learned from other explorers 
as to the presence or absence of human habita- 
tions and roads in the surrounding country. 
From all these data he will probably reach a con- 
clusion as to the probability or improbability of 
an automobile's being behind him, and if he is a 
mathematician he may state this probability as a 
percentage of all the possibilities which occur to 
him. Meantime, while following out all these 
lines of argument, he has stood with his back to 
the lights. 

On the other hand, if the traveler has been 



26 HOW to study: 

trained in the methods of modern science, while 
he may start with the same hypothesis, his de- 
ductions from it and his experimental tests of 
them may be somewhat as follows: 

i. Since the shadows are cast in front of him, 
the lights which cast them must be behind him 
and must be visible. To test this deduction, he 
turns and looks for the lights. 

2. If the lights are moving and are attached 
to an automobile,, the engine of the machine must 
be running; he accordingly listens for the engine. 

3. If the lights are approaching, the automo- 
bile, if such it is, must soon overtake him ; and he 
will wait for it and determine its character. 

4. If the lights are at rest, the machine, if 
there be one, has stopped; and he at once starts 
for it, meanwhile being guided by the lights. In 
the end, though his mental processes may be much 
simpler than those of the other traveler, he will 
know certainly whether or not the shadows are 
cast by the headlights of an automobile. 

A noted historical example of this difference. 

— In order that the foregoing comparison may 
not seem too much like a caricature, let us con- 
sider an historical instance of the manner in 
which two of the world's great men attempted to 
explain the same concrete and fairly simple phe- 



ILLUSTRATED THROUGH PHYSICS 27 

nomenon. Just two hundred years ago Newton 
published a treatise on Optics. One of the first 
experiments he describes consisted in making a 
small hole in the window shutter of a darkened 
room and in placing a three-cornered glass prism 
in the path of the beam of sunlight which entered 
through the hole and formed a spot of light on 
the opposite wall. Newton observed two im- 
portant changes due to the passing of the light 
through the prism. In the first place, he saw that 
the path of the beam of light was bent where it 
passed through the prism, so that the spot of 
light on the wall appeared in a new position, and 
in the second place he saw that what had before 
been a round patch of sunlight on the wall was 
now a band of rainbow colors. 

There seemed to be two possible hypotheses as 
to the cause of the colors. One was that they 
were already in the sunlight and had in some way 
been separated in passing through the prism ; the 
other was that the light in passing through the 
prism took something from the glass which gave 
it the colors. Newton chose the former hypothe- 
sis for trial. He guessed that all the colors of the 
rainbow were already in the sunlight, and that 
while all of them were bent aside in passing 
through the pr;sm, some of them were turned 
aside more than others. Looking at his band of 



28 HOW to study: 

light he saw that the blue end was farthest from 
the position originally occupied by the spot of 
light on the wall and that the red end was nearest 
to this position. So he concluded that if the band 
of colors was due to the bending of beams of 
different colored light by his prism, it must follow 
that a prism would cause a greater bending of 
blue light than of red light. This was the logical 
deduction from his hypothesis. To test this de- 
duction, he placed another glass prism in the 
beam of light which had passed through the first 
one, but placed it at right angles to the first and 
so that the red light would pass through it near 
one end and the blue light near the other end. He 
saw, as he had guessed, that the colored band 
was again turned aside in passing through the 
second prism,, and that the blue end of it was 
turned aside more than the red end. His deduc- 
tion was verified by experiment. 

Then he argued that if light is turned aside in 
passing through a prism, objects seen through a 
prism would appear displaced from their true po- 
sition, and that blue objects would appear more 
displaced than red objects. So he painted two 
squares side by side on a black screen, one blue 
and the other red, and looked at them through a 
prism. The squares appeared separated, and the 



ILLUSTRATED THROUGH PHYSICS 2Q 

blue one seemed more displaced than the red one. 
Thus his second deduction was verified. 

He next concluded that if the rainbow colors 
are caused by the separation of white light, it 
should be possible by combining all of them again 
to reproduce the original sunlight. This was a 
new deduction, and Newton tested it by two meth- 
ods. In one method he used a second prism paral- 
lel to the first and placed it so that it would bend 
the beam of light which had passed through the 
first prism back into its original path. He saw 
the spot of light appear upon the wall in the same 
place and of the same color as if it had not passed 
through either prism. This experiment not only 
verified his deduction, but it seemed to exclude 
the hypothesis that light in passing through a 
prism took color from the prism, as it was not 
reasonable to assume that one prism would put 
color into the light and the other prism take it out. 

Then Newton took seven little mirrors and 
mounted them so that he could place them in the 
band of colored light and allow a different color 
to fall upon each mirror. By tilting the mirrors 
so that they would all reflect their light to one 
spot he found that all the colors combined to pro- 
duce ordinary sunlight. It was in this way that 
Newton built up his theory of color. 



30 how to study: 

Ninety years after the publication of Newton's 
Optics, the German poet, Goethe, undertook to 
introduce another theory of colors based upon the 
hypothesis that the light in passing through the 
glass prism took up some unknown substance from 
the prism which combined with ordinary light to 
produce color. Goethe's fundamental experiment 
consisted in looking through a prism at a white 
wall, apparently expecting it to be seen in rain- 
bow colors. When he saw it white, except for a 
narrow band of red on one side and of blue on the 
other side, he at once decided that he had over- 
thrown Newton's theory of colors. His friends 
among scientific men tried to point out to him 
that what he had seen was exactly what might be 
predicted from Newton's theory, since if the wall 
were divided into narrow strips and the light 
from each strip were dispersed into the rainbow 
colors, these bands of colors would fall upon the 
neighboring strips in such a way that all the 
strips except those nearest to one edge would re- 
ceive all the colors of ordinary light. Along this 
edge the red light would be least deviated, so that 
this edge of the wall would be bounded by a red 
band. Along the opposite edge of the wall all the 
colors would appear displaced beyond the true 
edge of the wall, but since blue light is displaced 
more than the other colors it would extend be- 



ILLUSTRATED THROUGH PHYSICS 3 1 

yond all the other colors, and the wall would seem 
to be bounded on this side by a blue band. 

Goethe was apparently unable to reason to this 
deduction. In fact, he seems to have been almost 
incapable of using the logical process at all. His 
great countryman Helmholtz, in referring to this 
weakness of Goethe, says: 

But this step into the region of abstract 
conceptions, which must necessarily be taken 
if we wish to penetrate to the causes of phe- 
nomena, scares the poet away. 

For Goethe was a poet, and a poet, as a poet, 
has no use for the logical method of drawing de- 
ductions from hypotheses. The poet's generaliza- 
tions are not intended as hypotheses to be tested 
by the methods of science. 

Lowell tells us that "Poetry is not made out 
of the understanding/' and Goethe was a poet. 
So he wrote a book on the theory of color, which 
was largely made up of repeated statements of 
his own beliefs and of declamation against what 
he calls "the disgusting Newtonian white of the 
natural philosophers." Helmholtz says of this 
attempt at the discovery of scientific truth by 
intuition : 

We must look upon his color theory as a 
forlorn hope, as a desperate attempt to rescue 
from the attacks of science the belief in the 



32 HOW to study: 

direct truth of our sensations. And this will 
account for the enthusiasm with which he 
strives to elaborate and to defend his theory,, 
for the passionate irritability with which he 
attacks his opponent, for the overweening 
importance which he attaches to these re- 
searches in comparison with his other 
achievements, and for his inaccessibility to 
conviction or compromise. 

When Goethe found that, while his theory of 
color was received with some favor by the in- 
tuitional philosophers of his day, it failed to con- 
vince anyone trained in the use of the scientific 
method, he wrote a second volume, devoted in 
part to a reiteration of his theory, but mostly to 
an indecent attack upon Newton, who was, of 
course, long since dead. In this attack he calls 
Newton's reasoning "incredibly impudent/' says 
his theory might be "admirable for school chil- 
dren in a go-cart," and accuses Newton of fre- 
quently lying about his experiments, though all of 
them had been repeated many times by other 
physicists. 

Now that almost a century has passed since 
the publication of Goethe's theory of color, New- 
ton's interpretations of the phenomena of light 
and color are more firmly believed than ever, 
while their author is universally regarded as the 
greatest interpreter of nature that the world has 



ILLUSTRATED THROUGH PHYSICS 33 

ever known. Goethe is still regarded as the 
greatest of German poets, but his venture into the 
field of physical science is deplored by all his ad- 
mirers who know anything about it. 

How skill in the different steps of the scien- 
tific method has varied. — Not all physicists 
have been so expert in the steps of the scientific 
process as Newton seems to have been; and 
many of them have been much more skillful in 
some of the steps than in others. Accordingly, it 
has sometimes happened that part of the process 
leading to an important discovery has been car- 
ried through by one man and another part of the 
process by another man. This was true in the 
case of the discovery of the barometer and the 
measurement of atmospheric pressure. 

For hundreds of years the disciples of Aristotle 
had taught that the reason water can be raised by 
suction is because "Nature abhors a vacuum/' 
We find the same opinion still expressed by people 
who tell us that the warm air in a chimney rises 
and the cold air rushes in to take its place. After 
two thousand years, the students of Galileo found 
that a vacuum may apparently exist in a closed 
tube above a column of water thirty- four feet 
high, and hence that nature's abhorrence of a 
vacuum does not extend above thirty-four feet. 
Torricelli, in 1643, tried the experiment with a 



34 how to study: 

column of mercury, instead of water, and found 
that a vacuum could exist above a column 
of mercury only thirty inches high. Torricelli 
knew that a column of mercury thirty inches high 
weighs as much as a similar column of water 
thirty- four feet high. He guessed that the liquid 
column was in both cases held up by the pressure 
of the atmosphere, which must accordingly be as 
great as that of a layer of water thirty-four feet 
deep or a layer of mercury thirty inches deep. 
This was the hypothesis, — the second step in the 
scientific process. 

Torricelli was apparently unable to carry 
through the process. He did not know how to 
test his hypothesis, so he merely argued about it. 
But Pascal saw the next step. He said that if the 
atmosphere were a fluid pressing down upon the 
earth, its pressure would be less at an elevation 
than at sea level. So he carried a Torricellian 
tube of mercury to the top of a church steeple in 
Paris and thought that the mercury column stood 
lower than when on the ground. He then wrote 
to his brother-in-law, who lived near a moun- 
tain, to carry the tube to the top of the 
mountain and observe the effect. The brother-in- 
law did so, and the mercury column stood three 
inches lower on the top of the mountain than at 
its base. The scientific process was completed, 



ILLUSTRATED THROUGH PHYSICS 35 

and the mercurial barometer has ever since been 
used to measure the pressure of the atmosphere 
upon the earth. 

The contributions of different men in the 
discovery of universal gravitation. — While in 
the case just mentioned it took the work of two 
men to carry the scientific process through to 
completion, the establishment of a discovery in 
science sometimes involves the work of several 
men, each of whom carries through but a small 
part of the whole process. This was true of the 
discovery of universal gravitation. 

Three hundred and fifty years ago Tycho 
Brahe established the first astronomical observa- 
tory, and made a great number of measurements 
of the relative positions of the stars and planets 
at different times. He undertook to decide be- 
tween the theory of Ptolemy, which made the 
earth the center of the universe with the sun, 
moon, and stars revolving around it, and a theory 
that had been proposed but a short time before 
by Copernicus, which made the sun the center of 
the solar system, with the earth and the other 
planets revolving around it. 

Tycho was a skillful observer and made very 
accurate measurements, though the telescope had 
not then been invented; but he was unable to 
apply the scientific process to the facts which 



36 HOW TO study: 

he had discovered, and he finally decided in favor 
of the theory that the earth is the center of the 
universe. Years later he accepted as a student a 
young man named John Kepler, who proved to be 
a much abler scientific thinker than his master. 
Kepler, by using the measurements which Tycho 
had made, was able to compute with great ac- 
curacy the orbits of the planets about the sun and 
of the moon about the earth. He showed that all 
the planets move in elliptical orbits with the sun 
at one focus of the ellipse. 

So far the work of Tycho and Kepler was 
descriptive, though Tycho's work involved meas- 
urements which still command the admiration of 
astronomers, and Kepler's work involved some of 
the most famous mathematical calculations of the 
world. Neither gave any explanation of why the 
planets all moved in similar orbits about the sun, 
or even why they moved about the sun at all. 
It was sixty years later before an hypothesis ex- 
plaining these facts was proposed by Newton. 
Meanwhile, Galileo had experimented upon freely 
falling bodies and bodies rolling down inclined 
planes, and had made the discoveries which were 
later collected by Newton under the name of the 
laws of falling bodies. Galileo had also intro- 
duced the hypothesis of forces into mechanics, 
and had supposed that all bodies near the earth 



ILLUSTRATED THROUGH PHYSICS ^7 

are pulled toward it by a force which came to be 
known as the attraction of gravitation. 

Newton, while still a very young man, under- 
took to calculate under what conditions one body 
would move in an elliptical orbit about another 
body placed at one focus of the ellipse. He knew 
that when a heavy body is fastened to one end of a 
string and whirled around the hand which holds 
the other end of the string the hand must con- 
stantly pull upon the string or the body will not 
move in a curved path around the hand, but will 
continue to move in a straight path except 
as it is pulled toward the earth. His computa- 
tions told him that to make the body move in an 
elliptical path with the hand at one focus of the 
ellipse the pull upon the string must be greater 
when the weight is near the hand and less when 
it is farther away, and that the pull must increase 
just as fast as the square of the distance of the 
moving body decreases. This is called the law of 
the inverse square of the distance. Its calculation 
at that time was one of the great mathematical 
feats of the world. 

It seemed to Newton that the moon revolving 
about the earth must be pulled toward the earth 
by a force varying in this way. Then it occurred 
to him that this might be the same force which 
pulls all falling bodies to the earth. This was his 



38 how to study: 

hypothesis. He proceeded to calculate how far 
the moon must fall in one second toward the earth 
from its straight path if a body near the earth 
falls sixteen feet in one second and if gravitation 
decreases as the square of the distance between 
the falling body and the earth increases. The 
distance from the center of the earth to its sur- 
face and to the moon had both been calculated 
from astronomical measurements. Using these 
distances,, Newton calculated how far the moon 
should fall toward the earth in one second, and 
he found that it did not fall as far as it should 
if it were pulled by gravitation. Instead of fall- 
ing five and one-half hundredths of an inch, as 
it should from his computations, it falls only four 
and two-thirds hundredths of an inch in a second; 
hence he concluded that his deduction was not 
verified and, consequently, that his hypothesis 
was not sustained. 

As a consequence, Newton did not even tell 
any one of his hypothesis, much less attempt to 
defend it by argument; but accepted the test of 
his deduction. He says that he "laid aside at that 
time any further thought of the matter." So he 
went on with his investigations in optics,, his in- 
vention of the reflecting telescope and the sextant, 
and his work on the differential calculus that has 



ILLUSTRATED THROUGH PHYSICS 39 

been such a powerful tool in the hands of mathe- 
maticians since that time. 

Twenty years later a new measurement of the 
curvature of the earth was made by Pickard, 
which gave the radius of the earth as about four 
thousand miles, instead of 3436 miles, the dis- 
tance used by Newton in calculating how much 
the pull of gravitation should be at the dis- 
tance of the moon. Newton had found that the 
moon falls toward the earth one thirty-six hun- 
dredth as far in a second as does a body at the 
surface of the earth, and the new measurement 
of the earth's radius made it one-sixtieth of the 
moon's distance. Since the square of sixty is 
thirty-six hundred, the pull of the earth at the 
distance of the moon should be one thirty-six 
hundredth as great as at its surface, and New- 
ton's deduction was finally verified. 

Newton seemed at that stage to have proved 
that the same gravitation which makes the apple 
fall from the tree extends as far as the moon, 
and falls off with the inverse square of the dis- 
tance. But if gravitation may extend from the 
earth to the moon, why not to the sun? The 
earth moves about the sun in the same kind of 
curved path in which the moon moves about the 
earth. There should accordingly be a force which 



40 how to study: 

varies with the inverse square law between the 
earth and the sun, and Newton saw the whole 
solar system moving according to one general law. 

But this was, again, a new hypothesis, or rather 
an extension of his original hypothesis beyond 
the limits for which it had been verified. So New- 
ton inquired if there might not be some effect of 
the moon's gravitation on the earth which would 
enable him to test whether the sun produced a 
similar effect. There was. The tides were 
known to follow the apparent movement of the 
moon around the earth, and Newton was able to 
explain these by the difference in intensity of the 
moon's gravitation on the side of the earth near- 
est it and the side farthest from it. If the effect 
of the sun's gravitation reached the earth, it 
should also produce tides. Newton was able to 
point out these tides and show that they were of 
the proper magnitude, and hence that his hypothe- 
sis as to the extension of gravitation throughout 
the solar system was justified. Such was the 
scientific method of Newton. 

And such is the method by which scientific 
knowledge has always been acquired. It is the 
scientific method. It can be used in its entirety 
better in the study of physics than in the study 
of any other science. That is why physics 
has developed so much more rapidly than any 



ILLUSTRATED THROUGH PHYSICS 41 

other science. It is also the reason why one can 
acquire facility in the use of the scientific method 
better in studying physics than in studying any 
other subject. 

Importance of the scientific habit of thinking. 
— Is it important to acquire facility in the scien- 
tific habit of thinking? Let Professor John 
Dewey answer this question. He says : 

One of the only two articles that remain 
in my creed of life is that the future of our 
civilization depends upon the widening 
spread and the deepening hold of the scien- 
tific habit of mind; and that the problem of 
problems in our education is therefore how 
to discover and how to mature and make 
effective this scientific habit. Mankind so 
far has been ruled by things and by words, 
not by thought, for till the last few moments 
of history humanity has not been in posses- 
sion of the conditions of secure and effective 
thinking. 

Again, Professor Dewey says of the scientific 
method : 

It represents the only method of thinking 
that has proved truthful in any subject — that 
is what we mean when we call it scientific. 
It is not a peculiar development of thinking 
for highly specialized ends ; it is thinking so 
far as thought has become conscious of its 



42 HOW TO study: 

proper ends and of the equipment indis- 
pensable for success in their pursuits. 

If it is true that the mental process which we 
have called the method of science is "the only 
method of thinking that has proved truthful in 
any subject," it would seem that a training in this 
method should surpass in importance any other 
kind of mental training. It is true that the 
method cannot be used in its entirety in any other 
field of knowledge ; but it is likewise true that in 
any field where it cannot be applied, we cannot 
hope to attain to the same degree of certainty that 
we may in physical science. 

Significance of the scientific method in other 
fields than physics. — This, at least, it may do 
for us in other fields — it may teach us that 
opinions formed upon other matters are just 
as truly hypotheses until logically made deduc- 
tions from them have been verified as they are in 
physical science. It is here that argument has its 
proper place, which is, principally, to assist us in 
the formation of a clearer understanding of what 
may be involved in our hypothesis. Argument 
is commonly used to convert another to our hy- 
pothesis, rather than to test the hypothesis. An 
argument usually consists in a series of logical 
deductions from the hypothesis under considera- 
tion, but if such deductions are incapable of ex- 



ILLUSTRATED THROUGH PHYSICS 43 

perimental test they can be of value only when 
they lead to some relation which is known to exist, 
or when they lead to an absurdity. If the latter 
case should happen in a single instance the hy- 
pothesis must be abandoned or reconstructed so 
that it will avoid the absurdity. 

The mental attitude necessary. — Thus we 
may learn to approach the investigation of other 
subjects in much the same attitude of mind as we 
would begin the investigation of a question in 
physical science. This mental attitude has been 
very clearly described by Faraday in his lecture 
on "The Education of the Judgment." Faraday 
says: 

I believe that in the pursuit of physical 
science, the imagination should be taught to 
present the subject investigated in all pos- 
sible, and even in impossible views ; to search 
for analogies of likeness and (if I may say 
so) of opposition — inverse or contrasted 
analogies ; to present the fundamental idea in 
every form, proportion, and condition; to 
clothe it with suppositions and probabilities, 
that all cases may pass in review, and be 
touched, if needful, by the Ithuriel spear of 
experiment. But all this must be under gov- 
ernment, and the result must not be given to 
society until the judgment, educated by the 
process itself, has been exercised upon it. 
Let us construct our hypotheses for an hour, 



44 how to study: 

or a day, or for years ; they are of the utmost 
value in the elimination of truth which is 
evolved more freely from error than from 
confusion; but above all things let us not 
cease to be aware of the temptation they 
offer, or, because they gradually become 
familiar to us, accept them as established. 

This is a description of a kind of argument 
which may be applied in other fields as well as in 
physical science, and it suggests the value of dis- 
cussion with others ; for it is seldom that a single 
person is able to present all the possible, not to say 
the impossible, views of a very simple question. 
The danger of discussion is that we may have a 
much greater predilection for the points of view 
which we present ourselves than for equally sig- 
nificant points of view when presented by another, 
and the love for truth may easily be lost in the 
pleasure of successful combat or the struggle to 
maintain an hypothesis merely because it is one's 
own. Above all, it must not be forgotten that the 
establishment of truth is a mental, not a vocal, 
process. 

The danger from prejudice. — The tendency 
to a warping of the judgment through prejudice 
or through the expectation of a particular result 
is one of the most difficult things to overcome, 
even when our expectation is in no way influenced 



ILLUSTRATED THROUGH PHYSICS 45 

by our desires. It is much more so when the mat- 
ter under consideration has a personal bearing 
upon ourselves or our friends, or when it is con- 
cerned with a belief which has been inculcated by 
previous education. To overcome this danger 
the investigator in physical science usually tries 
to work out the experimental tests of his deduc- 
tions without knowing until they are finished 
what their bearing upon his hypothesis will be. 
Thus, a chemist may balance his sample to be 
analyzed by another body of unknown weight, so 
that he may remain ignorant of the proportions 
which he should obtain if his hypothesis is to be 
verified. Not until his analysis is complete will 
Ke weigh his counterpoise and compute the quan- 
tities which his hypothesis leads him to predict. 

Faraday, in the lecture already referred to, 
calls especial attention to the danger of having 
our judgment warped by prejudice, and we have 
already seen a deplorable example of this in the 
case of the poet Goethe. Faraday says: 

The inclination we exhibit, in respect to 
any report or opinion that harmonizes with 
our preconceived notions, can only be com- 
pared in degree with the incredulity we en- 
tertain towards everything that opposes 
them; and these opposite and apparently in- 
compatible, or at least inconsistent, conditions 



46 how to study: 

are accepted simultaneously in the most ex- 
traordinary manner. At one moment a de- 
parture from the laws of nature is admitted 
without the pretence of a careful examina- 
tion of the proof; and at the next, the whole 
force of these laws, acting undeviatingly 
through all time, is denied, because the testi- 
mony they give is disliked. 

/ will simply express my strong belief, 
that that point of self-education which con- 
sists in teaching the mind to resist its desires 
and inclinations, until they are proved to be 
right, is the most important of all, not only in 
things of natural philosophy, but in every 
department of daily life. 

Suggestions for overcoming prejudice. — It 

would appear from the above considerations that 
something more than a knowledge of the scientific 
method of procedure is necessary to one who 
would become an independent investigator of 
phenomena,, — that the mental traits which are 
generally included under the term, character are 
quite as important in scientific work as in other 
fields of endeavor. It would seem to follow that a 
complete discussion of how to study should at 
least advise one as to how the mind can be taught 
"to resist its desires and inclinations until they 
are proved to be right." 

This is more difficult than to describe the scien- 
tific method of thinking. The question is, How 



ILLUSTRATED THROUGH PHYSICS 47 

may one form a habit of developing hypotheses 
and of deducing their logical consequences with- 
out being influenced by the bearing which his con- 
clusions may have upon himself or upon other 
people ? In the opinion of the present writer, this 
habit may be acquired most easily in a field of in- 
vestigation where the personal applications are 
not appreciable. Thus, in the beginning, one is 
perfectly indifferent as to whether a suspended 
magnet sets north and south or east and west, or 
whether a free body falls sixteen feet or twenty 
feet in one second. His only concern is to de- 
termine the truth. If he continues to work with 
this sole end in view,, the determination of truth 
will gradually become a more and more important 
motive, and it may finally become so important as ) 
to be stronger than his prejudices and desires. 

Thus, the habit of seeking only the truth, com- 
bined with the fact that the scientific investigator 
who misrepresents the results of an investigation 
immediately receives the contempt of all men of 
science throughout the world, becomes a powerful 
corrective of prejudice and helps the investigator 
to be always "upon honor" with himself. 

In this connection, Professor Tyndall has said 
of the study of physics : 

It requires patient industry, and an 
humble and conscientious acceptance of what 



48 how to study: 

nature reveals. The first condition of suc- 
cess is an honest receptivity and a willing- 
ness to abandon all preconceived notions, 
however cherished,, if they be found to con- 
tradict the truth. And if a man be not 
capable of this self-renunciation — this loyal 
surrender of himself to Nature — he lacks, in 
my opinion, the first mark of a true philoso- 
pher. Thus the earnest prosecutor of sci- 
ence, who does not work with the idea of 
producing a sensation in the world, who loves 
the truth better than the transitory blaze of 
to-day's fame, who comes to his task with a 
single eye, finds in that task an indirect 
means of the highest moral culture. And 
although the virtue of the act depends upon 
its privacy, this sacrifice of self, this upright 
determination to accept the truth, no matter 
how it may present itself — even at the hands 
of a scientific foe, if necessary — carries with 
it its own reward. When prejudice is put 
under foot, and the stains of personal bias 
have been washed away — when a man con- 
sents to lay aside his vanity and to become 
Nature's organ — his elevation is the instant 
consequence of his humility. 

The kind of problem suitable for training in 
scientific method. — Thus far these pages have 
been devoted largely to an attempted description 
of the methods of the scientist as distinct from 
the methods of the scholar. It was stated in the 



ILLUSTRATED THROUGH PHYSICS 49 

beginning that there are two partially distinct 
methods which may, to some extent, be contrasted 
with each other. It is true, however, that it would 
be very difficult if not impossible to follow the 
scientific method to the exclusion of the other,, 
except as a mere matter of training. It would not 
be difficult to select for purposes of training a list 
of scientific problems which a student could be 
taught to solve by the scientific method without 
knowing what had, or had not, been done by 
others. So long as the purpose is training only, 
it is a matter of no consequence whether the 
answer of the question which is being put to 
nature is already known to others or not. How- 
ever, a teacher in putting such questions should 
know whether they are capable of being answered 
through the knowledge and skill already acquired 
by his pupil, and he can know this only if the 
question has already been answered, and if he is 
familiar with the process by which the answer 
has been obtained. Thus, for purposes of early 
training, a teacher is virtually compelled to con- 
fine himself to problems the answers to which he 
already knows; but it is necessary, if the student 
is to be trained in the scientific method of interro- 
gating nature, that he shall not know beforehand 
the answer which he is seeking. 

To the learner, any scientific question to which 



50 how to study: 

he does not know the answer may serve as a 
problem upon which to try his skill, but the danger 
is that the beginner will select a problem so 
difficult that no one has been able to solve it. In 
interrogating nature it is necessary to go very 
slowly, taking a single step at a time, and it is 
very difficult to break up the complex problems 
which seem to us nearest and most important into 
the simple problems of which they are built up. 
The most difficult task of a leader of investigation 
is to analyze the complex relations which exist 
everywhere in nature into simple relations which 
lend themselves to scientific investigation. Usu- 
ally there are not more than two or three men 
in the world working in physical science who are 
capable of making this analysis, and such men 
inevitably become world leaders in investigation. 
A man who belongs to this class must have both 
scientific insight and scholarship. De Morgan 
says: 

New knowledge, when to any purpose, 
must come by contemplation of old knowl- 
edge, in every matter which concerns 
thought; mechanical contrivance sometimes, 
not very often, escapes this rule. All the 
men who are now called discoverers in every 
matter ruled by thought, have been men 
versed in the minds of their predecessors, 



ILLUSTRATED THROUGH PHYSICS 5 1 

and learned in what had been before them. 
There is not one exception. 

The need of studying the methods of former 
scientists. — It should be noted that De Morgan 
lays stress upon the fact that a successful investi- 
gator should be "versed in the minds" of his 
predecessors, — not merely acquainted with the 
knowledge which they have possessed. This is 
equivalent to saying what has already been said in 
these pages,, that the way to learn the successful 
method in science is to study the methods of the 
men who have been the most successful investi- 
gators. This knowledge can only be acquired by 
reading the original descriptions of the investiga- 
tions as given by their authors ; it cannot be gained 
by reading second-hand descriptions compiled by 
other writers. To one who wishes to learn how 
to investigate physical phenomena, Tyndall's 
Sound or his Heat: A Mode of Motion is worth 
many textbooks on physics; and Faraday's Ex- 
perimental Researches in Electricity is of more 
value than all the libraries of scientific knowledge 
which have ever been compiled. 

Results of the scientific method. — We have 
already seen that until about three hundred years 
ago the human race had made little more prog- 
ress in its conquest of the physical universe than 



52 how to study: 

it had in other lines of human endeavor. Since 
that time we have made comparatively little prog- 
ress in the acquisition of knowledge concerning 
"men and their ways," while each decade now 
carries us farther than the preceding century in 
our comprehension of physical laws. 

Why have we not also made progress in our 
comprehension of things of the spirit? Within 
the possible span of a single life the physicist 
has taught the little whirligig of Hiero to do 
the work of millions of men, and thus to banish 
human slavery from the earth; he has re- 
leased the spirit that was imprisoned in the 
amber and made it his mighty servant and mes- 
senger of light; he has compelled the faithless 
wings of Icarus to bear him at will over moun- 
tains or sea; but the student of Literature, of 
Music, of Art, of Philosophy, of Morality, of 
man's relations to his Maker, must still go for his 
inspiration to the old masters. When only a few 
years ago a popular magazine took a vote of the 
leading thinkers of the world on the question 
"What are the seven wonders of the modern 
world?" six of the seven selected were achieve- 
ments of modern physics, and the seventh a re- 
cent achievement of an allied science. 

And we have seen why this is so. In the year 
1600, Dr. Gilbert announced to the world a new 



ILLUSTRATED THROUGH PHYSICS S3 

method of discovering the laws of the physical 
universe, and proved the accuracy of his method 
by discovering more of the laws of magnetism and 
of electricity than had all his predecessors since 
the beginning of time. That same year Giordano 
Bruno was burned at the stake in the streets of 
Rome for daring to defy the authority of the 
church in matters of the intellect ; and the young 
professor, Galilei Galileo, was risking a similar 
fate in dropping iron balls from the tower of Pisa 
to see if they would really fall with a speed pro- 
portional to their weight,, and in daring to recog- 
nize through his home-made telescope the spots on 
the sun, though ecclesiastical authorities had 
warned him that the sun must have no spots. For 
the first time in the history of our race men had 
begun to test their conclusions by experiment and 
to cross-question Nature experimentally to com- 
pel her to yield her secrets. It is this method of 
Gilbert and Galileo which has come to be called 
the scientific method, and it is due to the employ- 
ment of this method by a few individuals in each 
generation that our era has come to be known as 
"The Age of Science." 

Responsibility of teachers for centering at- 
tention on scientific method. — It would seem 
that it is only in the possession of this one method 
of learning "the rules of the game" that the hu- 



54 how to study: 

man mind is more competent than it was in the 
days of Aristotle or Socrates. And when we re- 
member that this method of science which has, 
within the memory of living man, so transformed 
our earth has been acquired by only a few indi- 
viduals among the many millions now living, we 
recognize the tremendous responsibility of the 
teachers who are chosen to guide beginners in the 
method of science. For the beginner, unless he 
be one of the world's great geniuses, must be 
guided by one who has learned to find his way 
about. No one travels in an unknown land by 
the aid of guide books, — he must depend rather 
upon his knowledge of physiography, his train- 
ing in woodcraft and his ability to supply his own 
necessities from the natural resources of the 
country. Until he has acquired these necessary 
accomplishments he must rely upon a guide who 
has acquired them. It will depend upon his use of 
the knowledge which he acquires from this guide 
whether he will ever be able to find his way about 
without assistance. And the teacher to whom is 
intrusted the training of the young men and 
young women who aspire to scientific attainment 
has not faithfully discharged his responsibility 
until he has given them a mastery of the only 
method of investigation which has ever been sue- 



ILLUSTRATED THROUGH PHYSICS 55 

cessfully employed by human beings to compel 
Nature to surrender her secrets for the benefit 
of mankind. 

Even the most enlightened members of our 
race still know very little about the physical uni- 
verse. They are pioneers who have only recently 
landed upon the shores of an unknown world. 
They have blazed a few trails into the surround- 
ing wilderness, and have ascended a few conspicu- 
ous mountain peaks. To some of these outlooks 
they have built easy roads, and have invited 
others to look out with them over the unknown 
country. They know that this country contains 
many wonderful mountains and fertile valleys 
which have never yet been trodden by the foot of 
man. It is the ambition of the pioneers of sci- 
ence first to blaze trails and then to find practical 
routes for roads into these "delectable moun- 
tains." It is the duty of the teacher of science 
to give the young men and young women who 
come to him a sufficient training so that they 
may at least be able to step aside from the 
beaten trails to gather the flowers and fruits 
which grow so profusely along them. Many will 
never venture far from the trail, but once in a 
long time will come a student with the courage 
and instincts of the pioneer, who wishes to go 



56 HOW TO STUDY 

beyond the landmarks of other men, and him the 
true teacher welcomes, not as a pupil, but as a 
companion and brother. 

It is these stalwart ones, who play their game 
of life single handed and away from their fel- 
lows, to whom the human race owes all it has 
achieved in the conquest of the physical universe. 
They are little known or heeded by the great un- 
thinking mass of their fellows, but no greater 
happiness can come to the true teacher of science 
than to stand as a guide and companion to a few 
of these chosen ones. 



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